BONNE TERRE, Mo. — Josh Williams was one of the youngest Ferguson activists protesting the police shooting death of unarmed black teen Michael Brown in 2014. He was arrested during the ensuing unrest over social justice issues that engulfed the Missouri city. Now, he’s incarcerated in a prison where convicted killers are executed.

“Inmate, where is your name badge? ” calls a guard at Williams, as he enters the prison’s visitor center with a smile on his face. Instead of the neon-green sunglasses and American flag bandana he wore as he protested in and around Ferguson during the protests, he’s wearing a gray scrub suit with white tennis shoes. The 6-foot Williams towers over the guards and other prisoners in the room, as an officer devotes him another name tag.

The 20 -year-old who had never been incarcerated before has now been behind bars for five months. Many activists have moved on to larger platforms to stand against police barbarism, and though Williams has more than 90 months left to serve, his passion for civil rights remains strong.

“Prior to everything, I had been working with youth and that’s still in my heart, ” Williams told HuffPost. “I’m going to continue to fight for other people in the the world.”

His sense of humor and willingness to tackle authorities made him stand out during the protests. He hollered at officials at public sessions, and stood face-to-face with heavily armed police during the unrest. MSNBC and The New York Times wrote about him. He marched alongside the philosopher Cornel West and spoke at a rally in Washington , D.C ., that the Rev. Al Sharpton organized.

Then, just before Christmas 2014 and a few months after Brown’s death, a cop fatally shot a teenager whom the officer told pulled a handgun on him outside of a gas station in Berkeley, a town near Ferguson. Protests erupted at the scene and there were conflicts with police officer. People looted a nearby QuikTrip convenience store and video footage showed Williams attempting to light a flame near the building’s entrance. St. Louis County police arrested him on Dec. 26, 2014. His bond amount was set at $30,000.

Many activists were in court to support Williams, as he pleaded guilty on Dec. 10, 2015, to first-degree arson, second-degree burglary and a misdemeanor for stealing. His attorney told the judge Williams had never been in any major difficulty before and that the medical evaluation had labeled his then-teenage client as “child-like.”

Yet Williams was sentenced to eight years in prison. That’s longer than other Missourians who committed similar crimes, including a 28 -year-old man who started a flame that caused$ 1 million damage at the University of Missouri and Stephens College, who was sentenced to six and a half years.

Williams became well known in and around Ferguson during the protests for wearingneon-green sunglasses and an American flag bandana, as he devoted passionate speeches during rallies.

Williams is now incarcerated in the Eastern Reception, Diagnostic and Correctional Center, about an hour’s drive south of St. Louis is Bonne Terre, Missouri, defined amid heavily wooded mounds. The facility holds around 2,000 inmates and is where the nation carries out executings. Missouri officials executed six people there last year — more than every other nation save Texas — and 10 people in 2014. That same year, authorities charged three former policemen with inmate abuse.

During the Ferguson unrest, Williams spent nights with other protesters to avoid sleeping in parking lots. Williams said he ran away from home in order to be more embedded in the protests. Those who knew him best during that time say his relationship with his mother was strained. However, Williams said he now talks to her every day.

Tony Rice, a fellow Ferguson protester, said he decided to welcome Williams into his home after find other demonstrators give the young man blankets and pillows for yet another night sleeping on the street. Williams had been staying with Rice for a few months before he was taken into police custody.

“He would stay up all night on my iPad listening to gospel music and reading the Bible, ” Rice told HuffPost.

“He was more comfortable around adults than people his own age. I guess when he got around children his own age he tried too hard.”

Before heading back to his cell, Williams’ asked if HuffPost could rely the message to back to Rice, that he needs his address in order to schedule a visit.

Williams said he wants his protest household to continue to speak-out against police killings. “Although I’m in here, I’m still fighting in here. Keep strong with it and I’ll be out soon, ” Williams said.

But first he must complete 85 percent of his eight-year sentence — more than six-and-a-half years. If he serves his full sentence, Williams would be released in 2023.

CORRECTION : An earlier version of this story misstated that ERDCC homes death row inmates. The facility is used as the site for executings .